I wonder if Gojou is going to make the crossdresser's clothing too?
We know he has trauma about being bullied for making hina dolls & dresses, but maybe the undoubtedly amazing costumes he'll make will help him gain confidence, & help lessen his anxiety about being "outed" as a dress/cosplay maker.
Social acceptance for your skills, rather than ridicule from your peers, is a big help for this sort of anxiety. I doubt it would "cure" him, but it would definitely help.
I also agree with
@valley_pauper that this manga is good about supporting people in what they want to do, not what you think they should do, so I doubt that Gojou will have to crossdress.
*IF* they make it so that he does crossdress, then it might be a flag for possible romance progression, seeing that the drama they're taking the costumes from has a woman (Gojou) selecting a man (Kitagawa) from group.
Idk, I hope they don't try to force this role onto someone that's obviously uncomfortable with themselves cosplaying/crossdressing, but then again high school is a horrid places filled with peer pressure & anxiety.